Can dragonflies migrate thousands of miles across the Indian Ocean, from India via the Maldives to Africa, and back again? An international research team led by Lund University in Sweden has used models and simulations to find out if the hypothesis could be true.
In 2009, marine biologist Charles Anderson put forward a hypothesis after observing globe skimmer dragonflies (Pantala flavescens) on the Maldives, that had flown in from what he assumed was India. When they flew off again, it was towards East Africa. Now, 12 years later, a group of researchers decided to investigate his claim.
Globe skimmer dragonflies are too small to be fitted with transmitters. Instead, the researchers examined its physiological aspects and calculated how long a globe skimmer dragonfly could stay airborne using the energy that can be stored in its body. In addition, the researchers used meteorological wind models to determine if there are winds that can facilitate the migration in both directions.
“Our study shows that this migration from India to East Africa is actually possible. However, the globe skimmer dragonfly can’t manage it using only the fat it can store in its body. It also requires favourable winds and these are present during certain periods of the year”, says Johanna Hedlund, a biology researcher at Lund University.
According to the simulated migration experiments using wind models, about 15 per cent of the dragonflies could manage the migration from India to Africa in the spring. In the autumn, 40 per cent could make the same journey in the opposite direction.